Data redundancy is used to ensure data correctness and consistency in the data storage technology. For example, Erasure Code (EC) is usually used for high efficient and durable storage. In recent years, cloud storage technology is constantly developing. For example, Elastic Cloud Storage (ECS) uses the latest trends in software architecture and development to achieve outstanding scalability, availability and performance. As the cloud storage develops, a growing number of technologies are applied into the cloud storage to achieve scalability, availability and high performance. EC can be extensively used in ESC scenario. However, when a part of the stored data changes, redoing an erasure code is resource consuming and other redundant codes also face similar problems.